1. Industrial Field
The present invention relates to an oral composition in which a nonionic antimicrobial or germicidal agent is formulated and more particularly, to an oral composition which exhibits excellent dental plaque-inhibiting and gingivitis-preventive effects by permitting the nonionic antimicrobial or germicidal agent to be stayed in the mouth over a long time.
2. Prior Art
It is known to formulate,, in oral compositions such as dentifrice, cationic germicidal effective ingredients such as chlorhexidine, cetylpyridinium chloride and the like so that formation of dental plaque is inhibited. These cationic germicides are disadvantageous in that they suffer considerable deactivation when used in the presence of surface active agents which are commonly used as a foaming agent in oral compositions. Thus, their efficacy cannot be shown satisfactorily.
On the other hand, nonionic antimicrobial or germicidal agents suffer a less degree of the deactivation with the surface active agents and show their activity to an extent in the presence of the surface active agents. Accordingly, attention has been recently paid to these agents as an effective ingredient of oral compositions. Among known nonionic antimicrobial or germicidal agents, triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) which has a very intense germicidal activity and is innoxious to human body has attracted attention because of the capability of inhibiting plaque from being formed by its intense germicidal action. In fact, there has been proposed incorporation, in oral compositions comprising triclosan, of zinc salts (Japanese Laid-open Patent Application Nos. 60-239409 and 60-239410), copper compounds (Japanese Laid-open Patent Application No. 62-89614), polyethylene glycol (Japanese Laid-open Patent Application No. 62-126116), phenolic compounds (Japanese Laid- open Patent Application No. 2-11511), and water-soluble calcium salts (Japanese Laid-open Patent Application No. 3-5416).
However, nonionic antimicrobial or germicidal agents typical of which is triclosan are very unlikely to reside in the mouth. Accordingly, known nonionic antimicrobial or germicidal agent-containing oral compositions do not show their plaque inhibiting effect satisfactorily. Hence, there is a demand for improving the above deficiency.